The Bay of Pigs is a day trip - I think it's about 2 hours towards Havana and then a sharp turn south. I know of people that left at 9am and were back for supper. I don't think there are resorts in that area.

Most dive shops have excursions there at least a couple of times each week. And they push it. Bargain with them - prices are not firm.

One thing to remember --- TAKE YOUR OWN GEAR!!! This is Cuba - gear is tattered, I wouldn't trust my life with it. Tanks are most often steel. Both DIN and yoke fittings can be found.